NGC 6025 (Open Cluster)
A bright open cluster in Triangulum Australe, about 2,500 light-years away and 110 million years old. From Guyana it stays low in the south.
Open cluster in Triangulum Australe. Magnitude 5.1.
Can you see it from Guyana?
From Georgetown (6.8° N) it climbs to 23° above the southern horizon at its highest; from Lethem (3.4° N), to 26° above the southern horizon. It is highest at midnight on the night of 21 May, in the middle of its season. The page works out tonight's rise, highest point and set for both towns in Guyana time (UTC-4), and where the Moon is.
What you'll see
- Your eyes: Visible to the eye only from a dark site, as a hazy knot of stars; lost in city skies. From Guyana it only reaches 23° above the southern horizon, so you need a clear, low view south. It lies 9.8° north-west of Atria.
- 10x50 binoculars: Resolves into dozens of stars.
- A small telescope (80 to 100 mm): A bright, loose group of stars at low power, low in the south from Guyana.
- A camera: Tiny on camera: it needs 2,000 mm or more of focal length on a tracking mount.
How big, how bright, how far
- Size on the sky: 11.4′, 37% of the Moon's width (the Moon is about 31′ wide).
- Brightness: magnitude 5.1. Fainter than Georgetown's faintest stars (4.3) but brighter than Lethem's (6.0).
- Distance: 2,480 light-years. The light reaching your eye left it about 2,480 years ago.
- True size: 8.2 light-years across its catalogued outline; light crosses it in 8.2 years.
Apparent size from OpenNGC (Mattia Verga), CC-BY-SA-4.0.
What it is made of
- Type
- Open cluster
- Mass
- About 1,300 times the Sun's mass, in its stars
- Age
- About 110 million years (range 71 million years to 200 million years)
What is in it, not measured:
- Stars born together: from one cloud of gas, at one time
How we know: Distance from Gaia parallaxes of its stars: Hunt & Reffert 2024, A&A 686, A42 (Gaia DR3 cluster catalogue, VizieR J/A+A/686/A42), retrieved 2026-10-21: NGC 6025 760 pc; statistical 2,476-2,481 ly (16th-84th percentile); Gaia DR3 parallax zero-point systematics (about 0.02 mas) add about 2%. True size: the apparent size times the distance (apparent size: OpenNGC (Mattia Verga, CC BY-SA 4.0), commit 4e2398a2). Mass: Hunt & Reffert 2024, A&A 686, A42 (Gaia DR3 cluster catalogue, VizieR J/A+A/686/A42), retrieved 2026-10-21, NGC 6025: total 1,261 ± 98 Suns.
More deep-sky objects: S Normae Cluster (NGC 6087) · NGC 6397 (Globular Cluster) · NGC 6124 (Open Cluster) · NGC 6231 (Northern Jewel Box) · NGC 6388 (Globular Cluster) · NGC 6752 (Globular Cluster)